1. Field of the Invention
Example embodiments of the present invention relate to methods of forming a more highly-oriented silicon layer and a substrate having the same. Other example embodiments of the present invention relate to methods of forming a more highly-oriented silicon layer having a larger grain size on an insulation substrate.
1. Description of the Related Art
In the field of display devices, flat panel displays are increasingly being used. Representative flat panel displays may be liquid crystal displays (LCDs), plasma display panels (PDPs) and/or organic light emitting devices (OLEDs). The development and production OLEDs is becoming increasingly common. LCDs and OLEDs driven by thin film transistors (TFTs) may have higher image quality and/or higher resolution. Larger-sized LCDs and OLEDs are also being developed. LCDs and OLEDs are also increasingly used in smaller size mobile displays (e.g., cellular phones).
Thin film transistors based on either amorphous silicon (A-Si) or polycrystalline silicon (poly-Si) are commonly used as switching devices.
Mobility of A-Si TFTs may be less than 1 cm2/Vsec. A-Si TFTs may be used as pixel transistors and driver integrated-circuits (ICs) may be externally mounted, increasing the cost and/or volume of the display system. Low temperature poly-silicon (LTPS) TFTs and system on glass (SOG) having no external driver ICs have increasingly been researched. If all external driver ICs are integrated on a glass substrate (e.g., a panel), connection wires between the panel and the external driver ICs may be unnecessary, decreasing defects generated in a TFT LCD and increasing the reliability of the TFT LCD. It may be a desired objective to manufacture a SOG having a panel in which a display system including data driver ICs, gate driver ICs and/or controllers are integrated. To obtain such an objective, it is desirous to obtain an LTPS having a mobility higher than 400 cm2/Vsec and a desired uniformity. However, the LTPS formed using conventional methods (e.g., excimer laser annealing (ELA), sequential lateral solidification (SLS) or metal-induced lateral crystallization (MILC)) may not achieve the desired quality.
Methods of forming polycrystalline silicon include a method of directly depositing polycrystalline silicon and a method in which amorphous silicon may be deposited and crystallized to form polycrystalline silicon.
Methods of directly depositing polycrystalline silicon may include a low pressure chemical vapor deposition (LPCVD), a plasma enhanced chemical vapor deposition (PECVD) or similar method. In the PECVD method, the deposition may be performed using a mixed gas at a temperature lower than 400° C. The PECVD method may not control grain characteristics of the polycrystalline silicon film. In particular, the orientation of grains of the polycrystalline silicon may not be uniform using the PECVD method such that the characteristics of a resulting polycrystalline silicon thin film may be degraded.